import pygame
import sys
from bullet import Bullet


def check_keydown_events(event, ai_settings, screen, myball, bullets):
   
    if event.key==pygame.K_RIGHT:
        myball.moving_right = True
    elif event.key==pygame.K_LEFT:
        myball.moving_left = True
    elif event.key==pygame.K_SPACE:
        
        #创建新炮弹并将其加入到编组bullets中
        if len(bullets) < ai_settings.bullets_allowed:
            new_bullet = Bullet(ai_settings, screen, myball)
            bullets.add( new_bullet)
def check_keyup_events(event, myball):
    if event.key==pygame.K_RIGHT:
        myball.moving_right = False
    elif event.key==pygame.K_LEFT:
        myball.moving_left = False
    
def check_events(ai_settings, screen, myball, bullets):
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            sys.exit()
        elif event.type == pygame.KEYDOWN:
            check_keydown_events(event, ai_settings, screen, myball, bullets)
            
        elif event.type == pygame.KEYUP:
            check_keyup_events(event, myball)
                
def update_screen(ai_settings, screen, myball, bullets):
    screen.fill(ai_settings.bg_color)
    for bullet in bullets.sprites():
        bullet.draw_bullet()
    myball.blitme()
    pygame.display.flip()

def update_bullets(bullets):
    bullets.update()
    for bullet in bullets.copy():
        if bullet.rect.bottom <= 0:
            bullets.remove(bullet)


    
